Device for releasing and interlocking the collapsible side walls of cases or containers, especially returnable containers made of plastic materials

ABSTRACT

The invention concerns a device for releasing and interlocking the collapsible side walls of a returnable container by means of a servo element that is provided with locking lugs at both ends and can be released by means of lifting. The side walls of the container can be folded inwards while they are being released.

[0001] The invention concerns a device for releasing and interlocking the collapsible side walls of cases or containers, especially returnable containers made of plastic materials, in particular, containers provided with four side walls that can be folded down onto the container bottom.

[0002] Containers and/or cases with four collapsible side walls are known and are extensively employed for the transport of objects both in households and in the storage and transportation industry. A multitude of different types of collapsible cases and/or containers are known, in which the side walls are either attached to the container bottom by means of articulated joints or are formed integrally with the container bottom, the fold line being defined by a kind of film hinge. A feature common to all containers with collapsible side walls is that the collapsible side walls are reversibly interlocked with each other at their upper edge.

[0003] To this end locking lugs are often provided or formed on the shorter side walls of the container that engage by means of a snap joint with corresponding locking hooks on the longer side walls when the containers are unfolded for assembly. But the releasing often proves difficult and toilsome, because the locking lugs have to be pressed out of their interlocked position with the locking hooks. The locking lugs and locking hooks are therefore often formed in a flexible manner, even though this can lead to the breakage of the hooks and/or the lugs during the interlocking and releasing operations. With a view to improving the releasing, there have been provided pivotably hinged servo elements in the side walls that bear upon the locking lugs and can be operated by applying pressure with a finger or a hand. When it is desired to release the joint, the servo element is pressed, whereupon the swivelling motion of the servo element deviates the locking lug out of its interlock position with the locking lug, after which the thereby released side wall can be collapsed onto the bottom of the container. Although these solutions are satisfactory, they are still capable of further improvement, especially as far as the handling aspects are concerned.

[0004] The invention therefore sets out to create a device for releasing and interlocking the collapsible side walls of returnable containers that has a simple and robust structure and can be operated with ease. In particular, the invention is to assure that when the container is gripped, which is usually done by getting hold of the handling opening or the gripping parts with the hand, the side walls of the case may also be released, if necessary by means of a single movement of the hand. Moreover, the releasing is also to make it possible to fold the side walls of the container inwards with the same move.

[0005] According to the invention, this aim is attained by means of the features set out in the characterizing parts of Claims 1 and 2, while useful further developments are characterized by the features described in the dependent claims.

[0006] In accordance wit the invention, a servo element is provided on the side wall capable of being folded inwards or a pair of opposite side walls capable of being folded inwards, especially on the outer faces of these walls, said servo element being capable of being displaced upwards by pulling it with the fingers. This upward movement of the servo element causes locking lugs forming part of the element to be lifted out of the position in which they interlock with the locking hooks of the adjacent side walls, so that the side walls released in this manner can then be folded inwards. Advantageously, the servo element with its gripping region will be arranged in the region of the handling opening or other gripping device of the container. The returnable container will naturally be gripped by means of this handling opening or other gripping device. Due to the fact that the servo element forms part of this region, in case of need the servo element can be very effectively gripped with the fingers, pulled upwards and, following the releasing thereby effected, the side wall can immediately be moved inwards. Advantageously, moreover, the servo element will be elastically pre-tensioned, so that a certain pressure will have to be exerted to obtain the releasing. Appropriate in this connection are straps or clips forming part of the servo element that bear against a part of the side wall, especially against an up-stand or a horizontal stiffener rib on the outer face of the side wall. This also assures that the operator will always have a good “feel” of the pressure he exerts on the servo element. When the servo element is released, it will automatically return to its rest position due to the return forces built up by the displaced straps or clips, so that the interlocking can also be achieved in a very simple manner. To this end one has to do no more than to get hold of the side wall by means of the gripping bar and/or the servo element, fold it upwards and then exert a slight pull on the servo element. When the side wall is in its vertical position, the servo element is released, so that the locking lug—due to the return forces acting on the servo element as a result of the elastic pre-tensioning—will automatically become inserted onto the locking hooks, so that the side wall will become locked in position. Furthermore, the device is structured in an extremely simple and robust manner and there is no need for instruction as to how the side walls have to be interlocked and released, because this is done automatically when the appropriately equipped servo element is gripped and pulled upwards

[0007] A number of embodiments will now be described with the help of the drawing, in which:

[0008]FIG. 1 shows a partial view of the shorter side wall of a returnable container in accordance with the invention in its working position, in which this side wall is interlocked with the longer side wall,

[0009]FIG. 2 shows a section view along the line A-A of FIG. 1,

[0010]FIG. 3 shows a side elevation of the servo element in accordance with the invention,

[0011]FIG. 4 shows a view from above of the servo or actuation element shown in FIG. 3, and

[0012]FIG. 5 shows a partial view similar to FIG. 1, but of another embodiment of the invention.

[0013] In FIG. 1 the reference number 1 designates a part of the shorter side wall of the returnable container, which is made up of a total of four side walls that can all be folded down onto the container bottom (not shown in the figure). In the figure the side wall 1 is seen from the outside, so that the side wall 1 can be folded down into the plane of the drawing. The reference number 2 designates the hinges formed at the bottom of the shorter side wall 1, which in this case are pinned hinges. By means of these hinges 2 the side wall 1 is pinned to the appropriately equipped container floor. On the left hand side the reference number 3 designates the longer side wall with which the side wall 1 can be interlocked, as will be described in greater detail further on. The side wall 3 is likewise provided with appropriate hinges 2 that serve to pin it into the appropriate half of the hinge on the container bottom. It can be seen that the hinges 2 of the longer side wall 3 are arranged somewhat higher than the hinges 2 of the shorter side wall 1. The reason for this is that the longer side walls 3 have to be folded down onto the previously folded shorter side walls 1 that rest on the container bottom. But this arrangement and the design of the pinned hinges are already state of the art, so that there is no need to discuss them in greater detail here.

[0014] A servo element, indicated by the reference number 6 and designed as a bar shaped somewhat in the manner of a coat hanger, is arranged on the outer face of side wall 1, which is provided with projecting stiffener ribs 4 in the horizontal direction and projecting stiffener ribs 5 in the vertical direction. This bar or servo element, which essentially extends over the entire length of the shorter side wall 1 (though only its left half is shown in the figure), has its ends accommodated and held in appropriate recesses of the vertical stiffening ribs 5 and is preferably guided therein also in the direction of the arrow F, i.e. the direction in which it is moved. At both its free ends the servo element 6 is provided with locking lugs 7, which—though shown in FIG. 1—can best be seen in FIG. 2 (section view). In the interlocked position illustrated by FIGS. 1 and 2, the locking lug 7 engages with a locking hook 8 of the longer side wall 3, so that the shorter side wall 1 is thereby interlocked with both the longer side walls 3. Such a locking device is of course provided on both sides, but for the sake of simplicity only the left half of side wall 1 is shown in FIG. 1.

[0015] As can best be seen from FIG. 1, the central region of the servo element 6 is aligned with or arranged along the lower edge of the customary handling (or gripping) opening 9 of the shorter side wall 1. Lastly, as already explained earlier on, the servo element 6, which has its left-hand end guided in a recess in the vertical stiffener ribs 5 (situated at 10), is resiliently pre-tensioned, for which purpose on each side of the servo element of the illustrated embodiment there are provided two arc-shaped spring clips 11 and 12 that face each other. These spring clips 11 and 12 have their upper ends bear against the horizontal stiffener rib 4 arranged immediately above them on the outer face of the side wall.

[0016] When the shorter side wall 1 has to be released and therefore folded down, the servo element 6 is gripped with the fingers in the region of the handling opening and lifted upward, so that the locking lugs 7 will likewise be lifted upward with respect to the locking hooks 8, whereupon the very move of gripping and lifting the servo element will also make it possible for the released shorter side wall 1 to be folded inwards. Whenever necessary, the mechanism may also be reversed, so that the release (.of the side walls.) will be obtained by means of a vertical downward motion of the servo element 6.

[0017]FIG. 3 shows the servo element on its own and permits one to see rather clearly that the central part 13 where it has to be gripped constitutes a downward bulge with respect to its two ends.

[0018] In the embodiment illustrated by FIG. 5 the servo element 6 is provided with a wavy surface in the region of the handling opening 9 in the shorter side wall 1, so that it matches the fingers of a hand and is therefore ergonomically designed. Of course, it is also possible for the gripping part 13 to be given some other shape, for example, appropriate recesses can be provided in the servo element to match the fingers of a human hand. In any case, whenever this is desired, gripping and lifting of the central part 13 will automatically release the shorter side wall 1 from the two longer side walls. When the servo element is lifted, the spring clips 11 and 12 will be pressed against the horizontal stiffener rib 4 and become pre-tensioned, so that a return force is built up. When the servo element 13 is released, the servo element 13 will be pressed downwards by the pre-tensioned spring clips 11 and 12 and, with the side wall 1 in the vertical position, will thus of its own accord arrive in the position in which the side wall is released from the longer side walls 3.

[0019] Other designs are, of course, possible. Depending on the width of side wall 1, the servo element 13 may also be subdivided into two servo elements, in which case one servo element will operate on the left-hand side and the other on the right-hand side. It is also possible for the servo element to be arranged in a different position with respect to the handling opening 9, possibly somewhat further below the lower edge of the handling opening 9 or even above it, in which case the gripping part 13 may also be arranged in the region of some other gripping element on the side wall, a gripping batten for example. In any case, it will be advantageous if the gripping part 13 is arranged in the region of the lower edge of the handling opening 9 as in the illustrated embodiment. When the container is to be released and folded, all that has to be done is to reach further downward with one or two fingers, or also with the entire hand, to lift the servo element 13, after which the released side wall 1 can be folded inwards without having to change the position of the hand. 

1. A device for releasing and interlocking the collapsible side walls of cases or containers, especially returnable containers with four side walls that can be folded down onto the container bottom, in which two opposite side walls, particularly the shorter side walls, can be releasably interlocked by means of locking lugs with the other two side walls, particularly the longer side walls, wherein the locking lugs (7) are made to engage with appropriate locking hooks (8) on the other two longer side walls (3), characterized in that for the interlocking and releasing movement there is provided a manually actuated servo element (6) that acts on at least one locking lug (7), the actuation part (13) of said servo element being arranged at a gripping part (9) for lifting the container and shaped in such a manner that the actuation part (13) for releasing the side wall (1) can be actuated while gripping the gripping part.
 2. A device for releasing and locking the collapsible side walls (1) of cases or containers, especially returnable containers with four side walls (1, 3) that can be folded down onto the container bottom, in which two opposite side walls, particularly the shorter side walls (1), can be releasably interlocked with the other two side walls, particularly the longer side walls (3), by making the locking lugs (7) engage with appropriate locking hooks (8) on the other two side walls/longer walls (3), especially in accordance with claim 1, characterized in that for the interlocking and releasing movement there is provided a manually actuated servo element (6) that acts on at least one locking lug (7), said servo element comprising an actuation part (13) that by means of an upward lifting movement parallel to the side wall (1) displaces the at least one locking lug, especially lifts it with respect to the locking hook (8), in such a manner that the appropriate side wall (1) becomes released and can be folded inwards.
 3. A device in accordance with claim 1, characterized in that the servo element is elastically pre-tensioned into the interlocked position.
 4. A device in accordance with claim 1, characterized in that at least one servo element (6) is provided on two opposite side walls (1).
 5. A device in accordance with claim 1, characterized in that the locking lug (7) is in each case formed at a free end of the servo element (6).
 6. A device in accordance with claim 4, characterized in that the servo element (6) extends over the length of the side wall (1).
 7. A device in accordance with claim 6, characterized in that one locking lug (7) is arranged at each of the two ends of the servo element (6).
 8. A device in accordance with claim 1, characterized in that the servo element (6) is formed as an elongated batten and is arranged on the outer face of the appropriate side wall (1).
 9. A device in accordance with claim 1, characterized in that the actuation section (13) is essentially arranged in the central region of the servo element.
 10. A device in accordance with claim 1, characterized in that the actuation section (13) is arranged in the region of the gripping part, especially in the region of the handling opening (9) and preferably at the lower edge of the handling opening (9) of the side wall and particularly below this edge.
 11. A device in accordance with claim 1, characterized in that the actuation section (13) is constituted by a part of the servo element that constitutes a downward bulge with respect to the remainder.
 12. A device in accordance with claim 1, characterized in that the servo element is elastically pre-tensioned on both sides.
 13. A device in accordance with claim 1, characterized in that the servo element (6) is provided with pre-tensioning devices, each of which consists of preferably arc-shaped spring clips (11, 12) that bear against a part of the side wall, especially a rib-like horizontal stiffener web (4) on the outer face of the side wall (1).
 14. A device in accordance with claim 1, characterized in that that the servo element (6) is held in recesses of vertical stiffener ribs (5) on the outer face of the side wall and is there guided for its lifting movement.
 15. A device in accordance with claim 1, characterized in that that the gripping part (13) of the servo element (6) has an ergonomic shape, especially corrugated and/or provided with appropriate hollows for the fingers.
 16. A device in accordance with claim 1, characterized in that two servo elements are provided on each side wall.
 17. A device in accordance with claim 2, characterized in that the servo element is elastically pre-tensioned into the interlocked position.
 18. A device in accordance with claim 2, characterized in that at least one servo element (6) is provided on two opposite side walls (1).
 19. A device in accordance with claim 2, characterized in that the locking lug (7) is in each case formed at a free end of the servo element (6).
 20. A device in accordance with claim 5, characterized in that the servo element (6) extends over the length of the side wall (1). 